To investigate the disturbance in The Weasel at Apollodorus’ Estate in Assassin’s Creed: Origins climb the pigeon tower to the platform at the back. Interact with the blood stain on the ground, the brazier on the ground and the pieces of wood and blood on the ground:

To investigate the disturbance climb the pigeon tower and interact with the brazier, blood stain and pieces of wood.

Go to below where the brazure was on the ground and investigate the charcoal:

To investigate the disturbance interact with the charcoal stain below where the brazier was.

Go to the area below the broken railing and interact with the blood and pieces of wood on the ground there:

To investigate the disturbance interact with the wood and blood below the broken railing.

Turn around, go past the haystack and towards the hay cart. Interact with the hay cart:

To investigate the disturbance go to the hay cart and interact with it.